1. Technical Field
This invention relates to a fluid mixing apparatus wherein a concentrated composition is aspirated and mixed with a diluent. More particularly, it relates to an automatic shut off assembly for a mixing apparatus wherein the shut off assembly is vacuum operated.
2. Background Art
Eductors are commonly employed to draw a concentrate from a source and mix it with a diluent such as water. A problem arises in making up the solution when an eductor is employed to draw the concentrate into a tank into which it is diluted. If the operator does not observe the container from which the concentrate is being drawn, water can continue to be drawn into the tank without any concentrate. This causes undesired dilution. A shut off valve provides an automatic shut off device to solve this problem.
It is known in the art to provide automatic shut off devices for fluid mixing systems. One such device is disclosed in U.S. Pat. No. 5,398,733 wherein a barrel liner L is drawn into a manifold 14 inlet port 38 to stop the flow of a concentrate.
In U.S. Pat. No. 3,351,238 a pressure activated switch 41 is disclosed in conjunction with an eductor 22 which senses a low supply in a storage vessel 25 to energize an indicating light.
The prior art does not provide an automatic shut off device for an eductor mixing system which is easily adapted to a container of relatively small volume and obviates the use of electricity. Thus, the need exists for an improved shut off device for an eductor mixing system.
The objects of the invention therefore are:
a. Providing an improved shut off device for an eductor mixing system. PA1 b. Providing a shut off device of the foregoing kind which does not rely on electricity for its operation. PA1 c. Providing a shut off device of the foregoing kind which is easily connected to a container for a concentrate as well as a filling vessel. PA1 d. Providing an improved shut off device of the foregoing type which is easily manufactured and assembled.